This is a Phase III multicenter, randomized, double-blind, double-dummy, parallel-group study to evaluate the efficacy and safety of two doses of GSK573719/GW642444 Inhalation Powder and GW642444 Inhalation Powder via a Novel Dry Powder Inhaler and tiotropium via HandiHaler when administered once-daily over a 24-week treatment period in subjects with chronic obstructive pulmonary disease (COPD). Subjects who meet eligibility criteria at Screening (Visit 1) will complete a 7 to10 day run-in period followed by a randomization visit (Visit 2) then a 24-week treatment period. There will be a total of 9 clinic study visits. A follow-up phone contact for adverse event assessment will be conducted approximately one week after the last study visit (Visit 9 or Early Withdrawal). The total duration of subject participation in the study will be approximately 26 weeks. The primary measure of efficacy is clinic visit trough (pre-bronchodilator and pre-dose) forced expiratory volume in one second (FEV1) on Treatment Day 169. Safety will be assessed by adverse events, 12-lead ECGs, vital signs, and clinical laboratory tests.